The invention relates to a method of controlling the tension in a driving belt of a continuously variable transmission, in particular for a motor vehicle. In such transmission, the driving belt is disposed between a primary pulley and a secondary pulley. Each pulley is provided with two conical discs, at least one of the conical discs being axially movable. The transmission also incorporates a torque converter which on the one side is coupled to the engine and on the other side to said primary pulley. By means of the torque converter, the torque to be generated from a stationary position is temporarily increased.
Such the method is generally know. With the known method and a known continuously variable transmission, a torque converter is generally used for increasing the torque delivered by the transmission when the motor vehicle drives off. Because the increased torque delivered by the torque converter must also be transmitted by the driving belt and, via the secondary pulley and an outgoing shaft, to the wheels of the motor vehicle, the known transmission systems are provided with means which ensure that the maximum tension in the known transmission systems never exceeds an allowable nominal tension which corresponds with a practically infinite life of the driving belt. This is necessary because the life of the driving belt will be limited when the nominal tension is exceeded. Thus the nominal tension is the absolute upper limit, which will not be exceeded in the known practical cases. The drawback of these known systems is that, given the known method and the known transmission systems, the drive-off torque of vehicles provided with such a known transmission is not optimal.